file name buffer in CDM_GETSPEC (corrected)

file name buffer in CDM_GETSPEC (corrected)

[
Sorry for previous patch. Ignore it please.
I polished the code just before sending and made a mistake.
]

Hello!

Starting from NT (not sure about '95), Windows is capable to handle
CDM_GETSPEC with NULL as lParam. It is handy for calculating
file name length if actual content does not matter while
it is undocumented behavior.

I suggest memcpy file name in FILEDLG95_Handle_GetFileSpec
if pointer is not zero only.

Besides this, MSDN clearly says passed buffer could be not large enough
for full file name. As far as I can see, WINE is fine for non-unicoded
flavour here and I suggest fixing for unicoded as well.